RU1790609C - Method of charging burden materials into blasting furnace - Google Patents

Abstract

Usage: in the steel industry, in particular to methods of steel smelting in bogie units. SUMMARY OF THE INVENTION: In an open-hearth furnace, lime and iron-containing material (LM), together with a material accelerating the process of slag formation, are loaded. As the material accelerating the process of slag formation, it is used heated in the process of the previous smelting on the thresholds of the furnace and partially calcined to lime (LFID). First, a portion of the LM is supplied to the front wall of the furnace, after which LFAR is charged in an amount of 50-80% of the total lime demand, then the rest of the LM and lime. As LM use an agglomerate or lightweight metal charge. 2 s.p. crystals, 1 tab.

Description

The invention relates to ferrous metallurgy, in particular to the production of steel in hearth steelmaking units.

The technological regime of the charge filling period to a large extent determines the course of the melting of the charge and slag formation, and therefore significantly affects the course of refining processes and the duration of melting.

A known method of steelmaking in the main open-hearth furnace, including layer-by-layer heating and mixing of bulk materials.

This type of filling ensures the formation of ferrous slag at the beginning of the smelting, in which lime or lime is relatively easily dissolved.

However, a disadvantage of the known method is the long filling time due to the need for mixing and large heat losses by radiation through open filling windows.

The closest to the claimed technical essence and the achieved effect is a method of inducing slag during steelmaking, including an additive in the filling of lime or lime together with a material that accelerates the process of slag formation, heating and melting of the charge. As a material that accelerates the process of slag formation, fluorite ore is used in an amount of 20-50% of the total consumption of lime or limestone.

This method allows to reduce the consumption of lime or lime, however, the reduction in cost is not achieved, because Additional costs arise when introducing fluorite ore into the filling. In addition, the latter contains fluoride compounds, as a result of which they are environmentally unsafe and their interactions

ABOUT

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action, as an accelerator of the process of slag formation, for a short time.

The aim of the invention is to reduce the consumption of limestone, reduce the cost of steel and improve working conditions.

The goal is achieved in that in the method of filling charge materials into an open-hearth furnace, comprising loading limestone together with a material accelerating the process of slag formation, in quality. The accelerating process of slagging of the material is carried out using heated in the previous smelting process on the thresholds of the furnace and partially annealed crushed limestone; first, part of the iron-containing material is fed to the front wall of the furnace, after which heated, partially annealed crushed limestone is fed from the furnace thresholds into 50-80% of the total limestone demand, then the rest of the iron-containing material and limestone are charged.

Before filling the heated, partially calcined crushed limestone from the furnace thresholds to the front wall, an agglomerate is fed as iron-containing material.

Before filling the heated, partially calcined crushed limestone from the thresholds of the furnace, a lightweight metal charge is supplied to the front wall as an iron-containing material.

The technical essence of the invention lies in the fact that, as a material accelerating the process of slag formation, use is made of 50-80% of the total demand of limestone, which is heated during the previous smelting on the thresholds of the furnace and partially calcined crushed limestone, and is put into the filling. Moreover, first, part of the iron-containing material (sinter or lightweight metal charge, or sinter with lightweight metal charge) is fed into the filling on the front wall of the furnace, after which heated, partially calcined crushed lime from the furnace thresholds is loaded onto it, then the rest of the iron-containing material and lime are loaded ka. Partial replacement of limestone by 50-80% of the total limestone requirement during the previous smelting process on the thresholds of the furnace and partially calcined by crushed limestone eliminates the need for heating the limestone to completely remove moisture, significantly reduces heat consumption for limestone decomposition and accelerates dissolution of CaO and slagging of silica. As a result, the formation of active base slag is significantly accelerated.

The amount of heat added to the filling process during the previous smelting at the furnace thresholds and partially calcined crushed limestone within the range of 50-80% of the total limestone demand is optimal and provides an accelerated slag formation process. Additive

0 heated during the previous smelting on the thresholds of the furnace and partially annealed crushed limestone less than 50% of the total demand of limestone, drastically reduces the rate of slag formation

5 due to the significant heat consumption for the decomposition of limestone.

The addition of heated during the previous smelting at the furnace thresholds and partially burnt crushed limestone to more than 80% of the total limestone demand also leads to a decrease in the rate of slag formation due to the small amount of carbon dioxide released during the decomposition of limestone.

5 The amount of limestone heated during the previous smelting on the thresholds of the furnace and partially calcined limestone in% ratio of the total amount of limestone poured into the furnace within

0 50-80% varies with changes in the composition of molten iron.

Thus, for example, with a high silicon content, the fraction of lime heated during the previous smelting at the furnace thresholds and partial calcined limestone is at the lower limit (see table).

A part of the iron-containing material (agglomerate or lightweight metal sinter, or agglomerate with lightweight metal) is fed to the front wall of the bath to form a protective layer, in order to prevent welding of CaO contained in the furnace heated during the previous smelting and partially burnt crushed to the front wall known ke. The amount of iron-containing material is determined by the condition that the front

0 walls in a thin layer.

The sequence of loading materials in the proposed method.

After the previous melting and refueling of the furnace to the front wall (slopes)

5, a part of iron-containing material, for example, 2-2.4 tons of agglomerate, is piled up through each window, then it is pushed heated during the previous smelting on the thresholds of the furnace and partially calcined crushed limestone is in the range of 50-80% of

general need is known. Pre-filling of iron-containing material, for example, agglomerate, and. the formation of a layer prevents overgrowing of the front slopes.

Before loading iron-containing material, it is not necessary to free the windows from heated during the previous smelting at the furnace thresholds and partially calcined crushed limestone, since there is enough free space in the window to introduce materials. Heated during the previous smelting on the furnace thresholds and partially annealed crushed limestone is pushed into the furnace and does not enter the front platform of the furnace, thereby improving working conditions.

After filling the charge materials into the furnace, the thresholds are crushed with lime hoppers in order to prevent slag and metal from flowing out of the furnace to the work site by measuring bins.

Example. Experimental smelting was carried out in 200-ton open-hearth furnaces operating with scrap - ore process. The furnace was lined in the following sequence: after the previous smelting was completed and the furnace was charged, the agglomerate with a basicity of 1.25 was loaded onto the front wall, the threshold was pushed in the amount of 50-80% of the total limestone demand and then the remaining part of the agglomerate and limestone.

The results of the experimental swimming trunks are presented in the table. In the same place, the averaged data of 100 swimming trunks of the current production and the results of melting carried out according to the technology of the prototype are given as the base.

An analysis of the data presented in the table shows that, when the requirements of the inventive method are met with respect to the operational parameter, an increase in the degree of desulfurization and dephosphorization is achieved by increasing the basicity of slag and reducing the duration of the melting and lapping periods, while the consumption of limestone and the cost of steel are reduced.

Claims (3)

1. A method of filling charge materials into an open-hearth furnace, comprising loading limestone together with a material that accelerates the process of slag formation, and iron-containing material, which is not isolated and so that, in order to reduce the consumption of limestone, reduce costs steel and improve working conditions, as the material accelerating the process of slag formation is used heated in In the process of the previous smelting on the thresholds of the furnace, partially burnt crushed limestone is known, while in the filling first a portion of the iron-containing material is fed to the front wall of the furnace, and then it is loaded with heated partially calcined crushed limestone from the thresholds of the furnace in an amount of 50-80% of the total limestone demand, then the rest of the iron-containing material is loaded and well known. 2. The method according to claim 1, characterized in that an agglomerate is supplied as iron-containing material to the front wall before filling the heated partially calcined crushed limestone from the thresholds of the furnace. 3. The method according to claim 1, characterized in that before filling the heated partially calcined crushed limestone from the furnace thresholds, a lightweight metal charge is supplied to the front wall as an iron-containing material. Heated during the previous smelting and partially calcined crushed is known to on the thresholds of the furnace. Table continuation